The present invention relates to a method of optimizing the band width distribution at the end of a band passing through a mill train.
One of the main problems in rolling bands, for example, band steel, is achieving a basic rectangular shape with a width that is constant over the band length. Vertical upsetting rollers are used in the mill train to control the band width. If the upsetting rollers are operated with a constant setting, the band becomes usually narrower at the band ends, i.e., at the band head and the band foot, than in the mid-part due to The asymmetric material flow and other effects. In order to prevent this from occurring, the adjustment position of the upsetting rollers is adjustable during the passage of the band, the adjustment being widened with respect to the mid-part as the band ends pass through in the form of short excursions, also known as short strokes. This adjustment correction at the band head and band foot is performed according to a curve (Short Stroke Control-SSC curve), which can be defined by preset parameters.
An object of the present invention is to produce a band width distribution at the band ends as close to the specified one as possible by providing a curve for the adjustment position of the upsetting rollers.
In In accordance with the present invention, the parameters for forming the curve according to which the position of the upsetting rollers is adjusted during the passage of the band ends are set on the basis of predictions concerning the rolling process using neural networks, with the prediction being continuously improved by on-line teaching of the neural networks on the rolling process. Preferably separate neural networks are used for the band head and the band foot. For consecutive passes of the same band, i.e., for several passes, separate neural networks may be used. If the number of passes is always the same, a single neural network can be used for determining the parameters of the curve of the upsetting rollers in the consecutive passes.